Photovoltaic waste-derived C@SiOx/ZnO composites: a scalable route to high-capacity and stable lithium-ion battery anodes

Silicon-based anodes deliver appealing specific capacity, yet their commercial viability is largely hindered by severe volume fluctuation and interfacial instability. To address these challenges while accounting for manufacturing costs, this study proposes an integrated spray-drying and pyrolysis strategy to upcycle micrometer-sized photovoltaic SiO x waste into a micro-nano spherical composite featuring an internally chemically bonded architecture (C@GSSOZ-b). Utilizing natural flake graphite as a conductive substrate, a multi-component carbon matrix (derived from pitch and polyvinylpyrrolidone) constructs a robust, chemically bonded network between the SiO x particles and the graphite. This structural paradigm not only facilitates continuous pathways for electron transport but also effectively dissipates the substantial mechanical stress induced during the lithiation/delithiation processes, thereby substantially mitigating the pulverization and detachment of active materials. Concurrently, the in-situ generated ZnO regulates the active interfaces, which considerably enhances the electrochemical interfacial compatibility and Coulombic efficiency. Consequently, this anode delivers excellent electrochemical performance, retaining 527.3 mAh g −1 after 776 cycles at 1.0 A g −1 (80.4% capacity retention), and maintaining 355 mAh g −1 after 1000 cycles at 5.0 A g −1 . Furthermore, practical feasibility is demonstrated in LCO||C@GSSOZ-b pouch cells, which exhibit superior cycling stability. Notably, accelerating rate calorimetry confirms a significantly lower heat generation rate, indicating enhanced thermal safety. This work resolves the component-structure stability trade-off in silicon anodes, providing a low-cost and industry-compliant solution for the development of high-energy and thermally safe lithium-ion batteries.